Scleroderma is an autoimmune disease associated with vascular injury, fibrosis, and inflammation. There is no known cure for scleroderma and current treatments are limited. Progress in the development of therapies to combat scleroderma has been hampered by a lack of knowledge of the pathophysiology that underlies this disease. We recently reported that miR-125b, a microRNA aberrantly expressed in scleroderma patients, regulates activation of NF?B. NF?B is a master regulator of pro-inflammatory cytokines associated with disease activity in scleroderma. We hypothesize that aberrant regulation of miR-125b in scleroderma Ms leads to enhanced activation of NF?B and pro-inflammatory cytokine production. The goal of this proposal is to determine how activation of NF?B is dysregulated in scleroderma macrophages and to evaluate how modulation of miR-125b alters inflammation associated with this disease. We propose to test the following hypotheses: 1. That NF?B activation differs between Ms derived from scleroderma patients vs. healthy controls. Activation of NF?B contributes to pro-inflammatory cytokine production characteristic of scleroderma. Experiments in this aim will elucidate effects on transcriptional activation, DNA binding activity and localization of components of the NF?B signaling complex. 2. That aberrant expression of miR-125b results in inappropriate activation of NF?B in scleroderma Ms. Our studies have shown that miR-125b enhances expression of ?B-Ras2, a negative regulator of NF?B signaling. Aberrant expression of miR-125b has been reported in scleroderma patients. We will assess how aberrant expression of miR-125b in Ms derived from scleroderma patients affects NF?B activation and pro-inflammatory cytokine production.